The government has been warned that moves to make speed cameras more visible could increase road deaths.

Campaigners have taken their case to the High Court in a bid to challenge government plans to make speed cameras more obvious to drivers.

Ministers last year advised the police and local authorities to paint cameras bright yellow. The order followed fears that speed camera traps were being used as revenue raisers.

But the Slower Speeds Initiative has joined forces with Transport 2000 to challenge the move.

They claim that making cameras visible to drivers will result in drivers slowing down as they approach them.

Paige Mitchell of the Slower Speeds Initiative believes that "only drivers who break the law need to worry about speed cameras".

"Speed cameras are a very cost-effective way to reduce crashes and save lives," she said.

"We hope the High Court will reverse this decision and allow the police discretion in enforcing speed limits. Let's have trials to see whether yellow or inconspicuous cameras are more effective."

Vicky Cann of Transport 2000 added: "The government has admitted that it made the decision to paint speed cameras yellow, not because it had evidence that yellow cameras were more effective in slowing drivers down, but because a few journalists were running scare stories about cameras trapping 'innocent motorists'.

"This is government decision-making by tabloid headlines and it sets a very dangerous precedent.''